How to extract fonts from OS X install DVD

Friends:

I often get the message when I open Keynote or Pages that some errors occurred and that the font "Helvetica" is missing. How can I get said font from my install DVD? I would install it using Font Books -> Add Fonts right?

The weird thing is also looking in Font Book, that Helvetica is there... but my main question is how to extract the fonts from the install DVD.

Thanks amigos, -Migs